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Novosadov [1.4K]
3 years ago
14

A car is driven on a straight track such that its displacement from the starting point is given as x = t + 2t2. What is the aver

age velocity (average rate of change of displacement) of the car between t = 2s and t = 4s?
Mathematics
1 answer:
romanna [79]3 years ago
7 0
Average rate of change = (x(4) - x(2))/(4 - 2) = ((4 + 2(4)^2) - (2 + 2(2)^2))/2 = ((4 + 2(16)) - (2 + 2(4)))/2 = ((4 + 32) - (2 + 8))/2 = (36 - 10)/2 = 26/2 = 13.

Therefore, average velocity is 13 m/s
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A circle passes through points A(7,4), B(10,6), C(12,3). Show that AC must be the diameter of the circle.
Artist 52 [7]

so we have three points, A, B and C, if indeed AC is the diameter of the circle, then half the distance of AC is its radius, and the midpoint of AC is the center of the circle, morever, since B is also on the circle, the distance from B to the center must be the same radius distance.

in short, half the distance of AC must be equals to the distance of B to the midpoint of AC, if indeed AC is the diameter.

\bf ~~~~~~~~~~~~\textit{middle point of 2 points } \\\\ A(\stackrel{x_1}{7}~,~\stackrel{y_1}{4})\qquad C(\stackrel{x_2}{12}~,~\stackrel{y_2}{3}) \qquad \left(\cfrac{ x_2 + x_1}{2}~~~ ,~~~ \cfrac{ y_2 + y_1}{2} \right) \\\\\\ \left( \cfrac{12+7}{2}~~,~~\cfrac{3+4}{2} \right)\implies \left( \cfrac{19}{2}~~,~~\cfrac{7}{2} \right)=M\impliedby \textit{center of the circle}

now, let's check the distance from say A to the center, and check the distance of B to the center, if it's indeed the center, they'll be the same and thus AC its diameter.

\bf ~~~~~~~~~~~~\textit{distance between 2 points} \\\\ A(\stackrel{x_1}{7}~,~\stackrel{y_1}{4})\qquad M(\stackrel{x_2}{\frac{19}{2}}~,~\stackrel{y_2}{\frac{7}{2}})\qquad \qquad d = \sqrt{( x_2- x_1)^2 + ( y_2- y_1)^2} \\\\\\ AM=\sqrt{\left( \frac{19}{2}-7 \right)^2+\left( \frac{7}{2}-4 \right)^2} \\\\\\ AM=\sqrt{\left( \frac{5}{2}\right)^2+\left( -\frac{1}{2} \right)^2}\implies \boxed{AM\approx 2.549509756796392} \\\\[-0.35em] ~\dotfill

\bf ~~~~~~~~~~~~\textit{distance between 2 points} \\\\ B(\stackrel{x_1}{10}~,~\stackrel{y_1}{6})\qquad M(\stackrel{x_2}{\frac{19}{2}}~,~\stackrel{y_2}{\frac{7}{2}}) \\\\\\ BM=\sqrt{\left( \frac{19}{2}-10 \right)^2+\left( \frac{7}{2}-6 \right)^2} \\\\\\ BM=\sqrt{\left( -\frac{1}{2}\right)^2+\left( -\frac{5}{2} \right)^2}\implies \boxed{BM\approx 2.549509756796392}

6 0
3 years ago
What is x?????????????
Mekhanik [1.2K]

Answer:

BGC=180-90

=90

BGC=BGE+EGC

BGC=BGE+15

90=BGE+15

BGE=90-15

BGE=75

BGE=AGF

AGF=X,

X =75

8 0
3 years ago
What percent of 3/5 is 9/10 ? <br> A. 1.5% <br> B. 7% <br> C. 15% <br> D. 67% <br> E. 150%
maw [93]
.67%
hope this helps.
0.6/0.9= 0.666667
7 0
3 years ago
Read 2 more answers
Use completing the square to solve for x in the equation (x+7)(x-9) = 25.
balandron [24]

Answer:

x = 1  ±√89

Step-by-step explanation:

We have the equation:

(x+7)(x-9) = 25

Using distributive property:

x(x-9) + 7(x-9) = 25

x²- 9x + 7x - 63 -25 = 0

x²- 2x - 88 = 0

To complete squares we need to add and subtract 1, as follows:

x²- 2x - 88 +1 -1 = 0

x²- 2x +1 -88 -1 = 0    (this is a perfect square)

(x - 1)² - 89 = 0

Solving for x:

(x - 1)² = 89

x - 1 = ±√89

x = 1  ±√89

6 0
3 years ago
Rewrite 20 = 8x + 4r
3241004551 [841]

Answer:

Step-by-step explanation:

20 = 8x + 4r can be rewritten in multiple ways.

1.  Reduce the coefficients:  5 = 2x + r

or

2.  Solve for r:  r = 5 - 2x

or

                                 5 - r

3.  Solve for x:  x = -----------

                                    2

4 0
3 years ago
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